Prochain séminaire / Next seminar

Many applications of microendoscopy, including brain imaging, requires minimally invasive devices to minimize damage during insertion in the tissue. Here we present a minimally-invasive endoscope based on a multimode fiber that combines photoacoustic and fluorescence sensing. Two different methods are presented. By learning the transmission matrix during a priori calibration step, a focused spot can be produced and raster-scanned over a sample at the distal tip of the fiber by use of a spatial light modulator. In a second approach, we demonstrate that a full-field illumination approach with multiple known speckle patterns can also provide diffraction-limited optical-resolution photoacoustic images without the need of the transmission matrix. We demonstrate that those two setups provide both photoacoustic and fluorescence microscopic images of test samples in vitro (fluorescent beads and red blood cells) through a single fiber.